Bicycle derailleur with a motor disposed within a linkage mechanism

ABSTRACT

A bicycle derailleur comprises a base member, a movable member for supporting a chain guide, a first link member pivotably coupled to the base member and to the movable member through respective first and second link pins, a second link member pivotably coupled to the base member and to the movable member through respective third and fourth link pins, and a motor having a drive shaft that defines a drive shaft vector. The first through fourth link pins define edges of a phantom space, wherein straight continuous phantom lines connecting ends of the first through fourth link pins in a non-crossing manner define remaining edges of the phantom space. At least a part of the primary motor housing is disposed in the phantom space, and the drive shaft vector points away from a plane containing the second and fourth link pins.

BACKGROUND OF INVENTION

The present invention is directed to bicycles and, more particularly, toa motorized bicycle derailleur.

Many current bicycles have electronically controlled bicycle components.For example, some bicycles include automatic transmissions whereinelectronically motorized front and rear derailleurs are automaticallycontrolled by a microcomputer based on bicycle speed. One type ofmotorized derailleur includes a motor that is spaced apart from thederailleur and connected to the derailleur by a conventional Bowdencable, wherein the motor pulls and releases the inner wire of the Bowdencable to operate the derailleur. Another type of motorized derailleurintegrates the motor with the derailleur so that the motor drive shaftdirectly moves the derailleur linkage mechanism. Such a configurationeliminates the requirement of a Bowden cable, thus making the overallderailleur mechanism more compact.

While a derailleur with an integrated motor has many advantages, it alsohas drawbacks. For example, the derailleur itself must be made larger toaccommodate the motor and related components. Since the derailleur ismounted to the side of the bicycle frame, the larger derailleurprotrudes laterally more than a conventional derailleur. This, in turn,creates the risk that the derailleur may be struck by rocks or otherobstacles when riding in rough terrain, or that the derailleur isdamaged or destroyed if the bicycle falls over.

Some motorized derailleurs include gear reduction mechanisms comprisinga plurality of variably sized interconnected gears so that higher speed,low torque motors may be used to precisely move the derailleur linkagemechanism. If the motor is integrated with the derailleur, then the gearreduction mechanism also must be integrated with the derailleur.Typically, the gear reduction mechanism is incorporated within thederailleur base member that mounts the derailleur to the bicycle frame.In such cases, the pivot shafts for the variably sized gears areattached to the base member, and possibly to the derailleur linkagemechanism and/or to the motor drive shaft. As a result, the entirederailleur sometimes must be disassembled in order to service the motoror the gear reduction mechanism. Furthermore, sometimes the pivot shaftsare permanently mounted to the base member, to the linkage mechanismand/or to the motor drive shaft such that the entire derailleur must bereplaced if the gear reduction mechanism is worn or damaged.

SUMMARY OF INVENTION

The present invention is directed to various features of a motorizedderailleur. In one embodiment, a bicycle derailleur comprises a basemember for attachment to a bicycle, a movable member for supporting achain guide, a first link member pivotably coupled to the base memberthrough a first link pin and pivotably coupled to the movable memberthrough a second link pin, a second link member pivotably coupled to thebase member through a third link pin and pivotably coupled to themovable member through a fourth link pin, and a motor having a primarymotor housing through which a drive shaft exits and defines a driveshaft vector that points away from the primary motor housing. The firstlink pin, the second link pin, the third link pin and the fourth linkpin define edges of a phantom space, wherein straight continuous phantomlines connecting ends of the first link pin, the second link pin, thethird link pin and the fourth link pin in a noncrossing manner defineremaining edges of the phantom space. At least a part of the primarymotor housing is disposed in the phantom space, and the drive shaftvector points away from a plane containing the second link pin and thefourth link pin. Additional inventive features will become apparent fromthe description below, and such features alone or in combination withthe above features may form the basis of further inventions as recitedin the claims and their equivalents.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a particular embodiment of a bicycle;

FIG. 2 is a more detailed side view of the rear derailleur;

FIG. 3 is a rear view of the rear derailleur;

FIG. 4 is a bottom view of the rear derailleur in a high speed position;

FIG. 5 is a bottom view of the rear derailleur in a low speed position;

FIG. 6 is a cross sectional view of the rear derailleur taken along lineVI-VI in FIG. 3;

FIG. 7 is an upper view of the derailleur base member;

FIG. 8 is a front view of the derailleur base member;

FIG. 9 is a bottom view of the derailleur base member with the gearreduction mechanism cover removed;

FIG. 10 is a cross sectional view of the derailleur base member takenalong line X-X in FIG. 8;

FIG. 11 is a cross sectional view of the derailleur base member takenalong line XI-XI in FIG. 8;

FIG. 12 is a schematic view of the derailleur motor disposed in aphantom space defined by the link pins;

FIG. 13 is a view of the gear reduction mechanism removed from the basemember; and

FIG. 14 is an exploded view of the gear reduction mechanism.

DETAILED DESCRIPTION

FIG. 1 is a side view of a particular embodiment of a bicycle 4. Bicycle4 comprises a frame body 8 constructed by welding tubing together in aconventional double diamond configuration. A front fork 12 is mounted tothe front of frame body 8 for rotation around an inclined axis, and ahandlebar assembly 16 is mounted to the top of front fork 12. A saddle18 is mounted to the upper middle part of frame body 8, a drivemechanism 20 is mounted to the lower part of frame body 8, a front wheel24 is rotatably mounted to the bottom of front fork 12, and a rear wheel28 is rotatably mounted to the rear of frame body 8. A front brakemechanism 32 is used to brake front wheel 24, and a rear brake mechanism36 is used to brake rear wheel 28.

Drive mechanism 20 comprises a pedal crank assembly 40 rotatably mountedat the bottom bracket of frame body 8, a front transmission 44 includinga front derailleur 46 mounted to frame body 8 and a plurality of (e.g.,two) sprockets 48 is mounted to the right side of pedal crank assembly40, and a rear transmission 50 including a rear derailleur 52 mounted tothe rear of frame body 8 and a plurality of (e.g., eight) rear sprockets54 mounted to rear wheel 28. Front derailleur 46 selectively engages achain 60 on one of the plurality of front sprockets 48, and rearderailleur 52 selectively engages chain 60 on one of the plurality ofrear sprockets 54.

Handlebar assembly 16 comprises a handle stem 64 mounted to the top offront fork 12 and a drop-style handlebar 66 mounted to the top of handlestem 64. Combined brake/shift lever assemblies 70 (only the right sidebrake/shift lever assembly is shown) of known construction are mountedat the opposite upper curves sides of handlebar 66. The left sidebrake/shift lever assembly 70 is used to operate front brake mechanism32 through a brake cable assembly 72, and the right side brake/shiftlever assembly 70 is used to operate rear brake mechanism 36 through abrake cable assembly 74. The brake/shift lever assemblies 70 also arestructured to manually control front transmission 44 and reartransmission 50 through a control unit 78 that is centrally mounted tohandlebar 66. Control unit 78 automatically electronically controls theoperation of front derailleur 46 and rear derailleur 52 through anelectrical cable assembly 84 in a known manner in response to signalsfrom a wheel rotation sensor comprising a reed switch 86 mounted toframe body 8 and a magnet 88 mounted to front wheel 24, wherein thesignals from reed switch 86 are received through an electrical cableassembly 90. Alternatively, control unit 78 electronically controls theoperation of front derailleur 46 and rear derailleur 52 in a knownmanner in response to the manual operation of the combined brake/shiftlever assemblies 70.

FIGS. 2 is a side view of rear derailleur 52, FIG. 3 is a rear view ofrear derailleur 52, FIG. 4 is a bottom view of rear derailleur 52 in ahigh speed position (when chain 60 engages the smallest rear sprocket54), and FIG. 5 is a bottom view of rear derailleur 52 in a low speedposition (when chain 60 engages the largest rear sprocket 54). As shownin those Figures, rear derailleur 52 comprises a base member 100structured to attach rear derailleur 52 to the rear of frame body 8, amovable member 104 pivotably supporting a chain guide 108, and first andsecond link members 120 and 124 coupled between base member 100 andmovable member 104 so that movable member 104 moves relative to basemember 100. Chain guide 108 rotatably supports a guide pulley 112 and atension pulley 116 for guiding chain 60 to engage selected ones of theplurality of rear sprockets 54.

First link member 120 has a first end 126 and a second end 134, whereinfirst end 126 is pivotably coupled to base member 100 through a firstlink pin 128, and second end 134 is pivotably coupled to movable member104 through a second link pin 138. Similarly, second link member 124 hasa first end 142 and a second end 150, wherein first end 142 is pivotablycoupled to base member 100 through a third link pin 146, and second end150 is pivotably coupled to movable member 104 through a fourth link pin154. In this embodiment, first end 142 of second link member 124 iskeyed to third link pin 146 by a flat 156 (FIG. 8) formed on third linkpin 146 so that second link member 124 and third link pin 146 rotate asa unit. A spring 160 (FIG. 6) is disposed between first link member 120and second link member 124 to remove the play in a gear reductionmechanism 210. In this embodiment, spring 160 is a coil spring with afirst end 162 and a second end 166, wherein first end 162 exerts abiasing force against first link member 120 approximately midway betweenfirst link pin 128 and second link pin 138, and second end 166 exerts abiasing force against second link member 124 in close proximity tofourth link pin 154.

Base member 100 comprises a generally cylindrical frame mounting portion170 and a drive housing 174. Frame mounting portion 170 includes amounting bolt opening 178 and a rotation stopper 180. A frame mountingbolt 182 passes through mounting bolt opening 178 for rotatably mountingframe mounting portion 170 to frame body 2. A conventional bias spring(not shown) is disposed within mounting bolt opening 178 and surroundsframe mounting bolt 182 for biasing a stopper plate 183 (FIG. 3)relative to frame mounting portion 170 so that a rotation stopper 184(FIG. 2) on stopper plate 183 abuts against rotation stopper 180 onframe mounting portion 170 in a known manner.

Drive housing 174 comprises a main housing 190 and a cover 194 attachedto main housing 190 through screws 198. Preferably, cover 194 isattached to a bottom of main housing 190 such that water or othercontaminants cannot enter into the inside of main housing 190. Mainhousing 190 is integrally formed as one piece with frame mountingportion 170 and defines a drive component space 202 (FIG. 6) for housinga drive component such as an electric motor 206 and gear reductionmechanism 210.

Motor 206 comprises a primary motor housing 214 (FIG. 8) disposed withina generally cylindrical motor mounting portion 218 of main housing 190,a motor drive shaft 222 (FIG. 10) extending outwardly from primary motorhousing 214 and defining a drive shaft vector V that points away fromprimary motor housing 214, and a motor shaft drive gear 230 attached tothe free end of motor drive shaft 222. In this embodiment, drive housing174 is structured such that the entire primary motor housing 214 isdisposed within base member 100.

As shown schematically in FIG. 12, first link pin 128, second link pin138, third link pin 146 and fourth link pin 154 define edges of aphantom space 250, and straight continuous phantom lines PH1-PH8connecting ends of first link pin 128, second link pin 138, third linkpin 146 and fourth link pin 154 in a non-crossing manner defineremaining edges of phantom space 250. Furthermore, first link pin 128and third link pin 146 lie in a plane P1, and second link pin 138 andfourth link pin 154 lie in a plane P2. Drive shaft vector V points awayfrom plane P2, preferably but not necessarily such that a relative angleθ between drive shaft vector V and plane P2 is in a range between 45degrees and 135 degrees when measured in a plane P3 that isperpendicular to first link pin 128, second link pin 138, third link pin146 and fourth link pin 154. At least a part of primary motor housing214 is disposed within phantom space 250. As a result of these features,alone or in combination, base member 100, and hence rear derailleur 52,may be made more compact.

FIG. 13 is a view of gear reduction mechanism 210 removed from drivehousing 174, and FIG. 14 is an exploded view of gear reduction mechanism210. In this embodiment, gear reduction mechanism 210 is aself-contained unit that is housed within drive component space 202 ofdrive housing 174 such that gear reduction mechanism 210 is disposedentirely within base member 100 and can be removed as a unit from basemember 100. As shown in FIGS. 13 and 14, gear reduction mechanism 210comprises a gear support 300 that supports a gear reduction unit 298 anda position sensing unit 299. Gear reduction unit 298 comprises a mainsupport 302 including a main support cover 303, both of which may bemade of a plastic material, a first gear 304 rotatably coupled to mainsupport 302 through a pivot shaft 306 for engaging motor shaft drivegear 230 so as to receive rotational drive force from motor 206; asecond gear 310 rotatably coupled to main support 302 through a pivotshaft 312 for engaging a driven portion or component such as a linkdrive gear 314 (FIG. 9) that rotates integrally with third link pin 146and second link member 124; and a plurality of intermediate gears 316,318, 320 and 322 coupled between first gear 304 and second gear 310 forfurther reducing the rate of rotation between motor shaft drive gear 230and link drive gear 314. Smaller diameter intermediate gear 316 isintegrally formed with first gear 304 and engages larger diameterintermediate gear 318. Intermediate gear 318 is integrally formed withsmaller diameter intermediate gear 320 and spaced apart therefrom by aspacer 319, wherein intermediate gears 318 and 320 are rotatably coupledto main support 302 and main support cover 303 through a pivot shaft321. Intermediate gear 320 engages larger diameter intermediate gear322, wherein intermediate gear 322 is integrally formed with second gear310.

Main support 302 includes a semicircular bottom portion 324 with anopening 328 for receiving third link pin 146 therethrough, a main bodyportion 332, a motor interface portion 336, and main support cover 303.Main body portion 332 includes a gear cavity 340 for housing first gear304 and intermediate gear 316, a gear cavity 344 for housingintermediate gears 318 and 320, and a gear cavity 348 for housingintermediate gear 322. Gear cavity 340 includes a pivot shaft opening352 for supporting a lower end of pivot shaft 306, gear cavity 344includes a pivot shaft opening 356 for supporting a lower end of pivotshaft 321, and gear cavity 348 includes a pivot shaft opening 360 forsupporting a lower end of pivot shaft 312. A pivot shaft opening 362 isformed in main support cover 303 supporting an upper end of pivot shaft321. A bushing 364 is disposed in gear cavity 348 between intermediategear 322 and main body portion 332 to stabilize intermediate gear 322.Motor interface portion 336 is provided for stably interfacing motor 206with main support 302 and includes a drive shaft receiving member 366with a drive shaft receiving opening 368 for receiving drive shaft 222therethrough so that motor shaft drive gear 230 may engage first gear304.

Position sensing unit 299 is operatively coupled to first gear 304, andit comprises an optical position sensing member 370 rotatably supportedto a position sensing unit support 374 (which may be made of a plasticmaterial) through a pivot shaft 376, a phototransmitter/photoreceiverunit 378 coupled to position sensing unit support 374, a smallerdiameter position sensing reduction gear 382 that rotates integrallywith position sensing member 370, and a larger diameter position sensingreduction gear 386 rotatably coupled to position sensing unit support374 through pivot shaft 306. Position sensing unit support 374 includesa pivot shaft opening 387 for supporting an upper end of pivot shaft312, a pivot shaft opening 388 for supporting an upper end of pivotshaft 376, and a pivot shaft opening 389 for supporting an upper end ofpivot shaft 306. A bushing 391 is disposed between second gear 310 andposition sensing unit support 374 to stabilize second gear 310. Positionsensing reduction gear 386 includes a coupling shaft 390 with a pair ofkey projections 394 that engage a corresponding pair of key openings 398in first gear 304 so that position sensing reduction gear 386 rotatesintegrally with first gear 304. As a result of position sensingreduction gears 382 and 386, position sensing member 370 also rotatesintegrally with first gear 304, but at a faster rate.

It should be readily apparent that main support 302 rotatably supportsfirst gear 304, second gear 310 and the plurality of intermediate gears316, 318, 320 and 322 as a substantially self-contained unit, andposition sensing unit support 374 rotatably supports position sensingmember 370, phototransmitter/photoreceiver unit 378 and position sensingreduction gears 382 and 386 as a substantially self-contained unit. As aresult of this structure, gear reduction mechanism 210 may be removedfrom base member 100 as a unit for replacement or repair, and gearreduction unit 298 and position sensing unit 299 may be separated fromeach other as substantially self contained units for separatereplacement or repair. Furthermore, forming gear support parts such asmain support 302, main support cover 303 and position sensing unitsupport 374 from a plastic material reduce manufacturing costs and alsoreduces the noise from the operation of the gears.

While the above is a description of various embodiments of inventivefeatures, further modifications may be employed without departing fromthe spirit and scope of the present invention. For example, the size,shape, location or orientation of the various components may be changedas desired. Components that are shown directly connected or contactingeach other may have intermediate structures disposed between them. Thefunctions of one element may be performed by two, and vice versa. Thestructures and functions of one embodiment may be adopted in anotherembodiment. It is not necessary for all advantages to be present in aparticular embodiment at the same time. Every feature that is uniquefrom the prior art, alone or in combination with other features, alsoshould be considered a separate description of further inventions by theapplicant, including the structural and/or functional concepts embodiedby such feature(s). Thus, the scope of the invention should not belimited by the specific structures disclosed or the apparent initialfocus or emphasis on a particular structure or feature.

1. A bicycle derailleur comprising: a base member for attachment to abicycle; a movable member for supporting a chain guide; a first linkmember pivotably coupled to the base member through a first link pin andpivotably coupled to the movable member through a second link pin; asecond link member pivotably coupled to the base member through a thirdlink pin and pivotably coupled to the movable member through a fourthlink pin; wherein the first link pin, the second link pin, the thirdlink pin and the fourth link pin define edges of a phantom space;wherein straight continuous phantom lines connecting ends of the firstlink pin, the second link pin, the third link pin and the fourth linkpin in a non-crossing manner define remaining edges of the phantomspace; a motor having a primary motor housing through which a driveshaft exits and defines a drive shaft vector that points away from theprimary motor housing and toward a terminating end of the drive shaft;wherein at least a part of the primary motor housing is disposed in thephantom space; and wherein the drive shaft vector that points toward theterminating end of the drive shaft also points away from a planecontaining the second link pin and the fourth link pin at a locationwhere the drive shaft exits the primary motor housing.
 2. The derailleuraccording to claim 1 wherein a relative angle between the drive shaftvector and a plane containing the second link pin and the fourth linkpin is in a range between 45 degrees and 135 degrees when measured in aplane perpendicular to the first link pin, the second link pin, thethird link pin and the fourth link pin.
 3. The derailleur according toclaim 1 wherein the drive shaft is coupled for moving the movable memberthrough a gear connection.
 4. The derailleur according to claim 3wherein the gear connection comprises a gear reduction mechanism.
 5. Thederailleur according to claim 1 wherein at least a portion of theprimary motor housing is disposed within the base member.
 6. Thederailleur according to claim 1 wherein at least a portion of the driveshaft is disposed within the base member.
 7. The derailleur according toclaim 1 wherein at least a portion of the primary motor housing isdisposed within the base member, and wherein at least a portion of thedrive shaft is disposed within the base member.
 8. The derailleuraccording to claim 7 wherein the drive shaft is coupled for moving themovable member through a gear connection.
 9. The derailleur according toclaim 8 wherein the gear connection comprises a gear reductionmechanism.
 10. The derailleur according to claim 7 wherein the entireprimary motor housing is disposed within the base member, and whereinthe entire drive shaft is disposed within the base member.
 11. Thederailleur according to claim 10 wherein the drive shaft is coupled formoving the movable member through a gear connection.